Niní tells the story of Nina Gómez, an innocent girl, somewhat distracted, spontaneous and with a big heart, who has been left alone with her grandfather, the gardener of the embassy in which they live. The life of Nina it is altered with the arrival of the new ambassador, Tomás Parker, an orderly and distant man. Tomás Parker arrives at the mansion accompanied by his ambitious secretary Celina Martínez Paz and his four adopted children. Niní, who quickly becomes fond of the kids, she must overcome several obstacles to be able to remain in the embassy next to them. To the point that she ends up disguising herself as a man and becoming Nicolás, the new ambassador's driver. Niní will fall madly in love with Tomás just like he does with her. From now on a delicious plot begins to develop where Niní, with its simplicity and brightness, will reach the heart of the Parkers, transmitting values that neither power nor money can get, freedom, love and a sense of humor outside of the usual.